1. Field of the Invention
The present invention relates to a method of driving a light source, a light source apparatus for performing the method, and a display apparatus having the light source apparatus. More particularly, the present invention relates to a method of driving a light source for driving a light source including a plurality of light-emitting blocks by light-emitting block, a light source apparatus for performing the method, and a display apparatus having the light source apparatus.
2. Description of Related Art
Generally, a liquid crystal display (LCD) apparatus includes an LCD panel displaying an image using optical transmittance of liquid crystal molecules and a backlight assembly disposed below the LCD panel to provide the LCD panel with light.
The LCD panel includes an array substrate, a color filter substrate and a liquid crystal layer comprising the liquid crystal molecules. The array substrate includes a plurality of pixel electrodes and a plurality of thin-film transistors (TFTs) electrically connected to the pixel electrodes. The color filter substrate faces the array substrate and has a common electrode and a plurality of color filters. The liquid crystal layer is interposed between the array substrate and the color filter substrate. When an electric field generated between the pixel electrode and the common electrode is applied to the liquid crystal layer, an arrangement of liquid crystal molecules of the liquid crystal layer is altered to change optical transmissivity, so that an image is displayed. Here, the LCD panel realizes a white image of high luminance when an optical transmittance is maximized, and the LCD panel realizes a black image of low luminance when an optical transmittance is minimized.
To prevent a contrast ratio (CR) of an image from being decreased and to minimize power consumption, a method of locally dimming a light source has been developed, which controls an amount of light of the light-emitting blocks in accordance with luminance of an image corresponding to the light-emitting blocks. In the method of local dimming, the light source is divided into a plurality of light-emitting blocks to control an amount of light of the light-emitting blocks in correspondence with dark and bright display areas of the LCD panel corresponding to the light-emitting blocks.
Generally, when the method of local dimming is used, a gradation average value of pixel data may be used. The determination of the gradation average value is a low power consumption method for determining a duty of the light-emitting blocks. When the duty of the light-emitting blocks is determined by using the gradation average value, a driving duty of the light-emitting blocks is varied in accordance with a position of an image, so that luminance of an image is varied due to a variation of the driving duty. Thus, in a case of a moving image in which a predetermined image having high gradation in a dark background image and small amplitude is moved, luminance differences are generated due to a duty variation of the light-emitting blocks in accordance with a position of the predetermined image so that flicker is displayed in the LCD panel.